Computers, often from a low-level systems perspective. Note that I speak for myself, not my employer.

Monday, November 14, 2005

VT hits the streets

Intel's Virtualization Technology (VT) has hit the streets. For those just tuning in, VT, like AMD's competing initiative SVM, nee Pacifica, provides hardware support for CPU virtualization in the x86. I've spent a good deal of the last year working on supporting VT in VMware's VMM; this work is currently available in the public beta of VMware Workstation 5.5, so, if you have a really, really new Intel CPU and are curious about how this VT stuff works, please give our code (and Intel's new hardware) a try.

What does this all mean for VMware? Opinions vary, of course. When VT and Pacifica were first announced, there was a lot of knee-jerk slashdot triumphalism of the form, "Ha! We don't need VMware anymore because it will all be in hardware!!!" Of course, there's a lot more to VMware's software than just multiplexing CPUs. There's memory, a chipset, peripherals, undoable disks, virtual networks hooked up in complicated topologies with configurable bitrates and lossiness, and all sorts of other stuff that's hard to imagine doing in hardware.

It is true that Pacifica and VT sidestep the classical impossibility result about x86 virtualization. On the one hand, if VMware hadn't figured out how to square that circle in 1998, I don't think we'd be where we are as a company today. But, on the other hand, we're far past the point where VMware lives and dies by a single systems programming parlor trick. Raw technology solutions for multiplexing an x86 CPU are already freely available. See, for example, QEMU. But, as cool as QEMU is, it doesn't really directly compete with VMware Workstation, because, e.g., you can't sync your ipod with a multiprocessor windows guest running inside of QEMU.

In 1998, VMware Workstation 1.0 was a singing dog: the miracle wasn't that it sang well, but that it sang at all. However, in the intervening seven years, our software has become more than a curiosity. Stretching the analogy far past where wisdom suggests, we've taught that dog to be a colorful, original interpreter of Western music's canon, and we expect that dog to soon shock the world by crafting original, poignant compositions. Who cares if the landscape is cluttered with other mutts practicing their scales?